<!doctype html>
<html>
<head>
<meta charset="utf-8">
<title></title>
</head>

<body>
<form id="myform"  method="post" action="#">
    <select name="grade" id="grade">
        <option value="1">初级</option>
        <option value="2">中级</option>
        <option value="3">高级</option>
        <option label="提示文本" value="">未知</option>
        <option>不明确</option>
    </select>
</form>
<script>


var form = document.getElementById("myform");
var grade = form.elements["grade"];  
grade.onchange = function(){                     
	var selIndex = grade.selectedIndex;
	var selOption = grade.options[selIndex];
	console.log("  index: " +grade.selectedIndex + "\ntext: " + selOption.text + "\nvalue: " + grade.value);            
}
</script>
</body>
</html>
